Integrated Touch Sensing Units in LCD Panels
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Solution Overview
Problem
Touch screen LCDs face challenges such as increased cost, yield decrease, and luminance deterioration due to the addition of a separate touch screen panel, and existing sensing units are prone to generating incorrect sense data signals due to impulse noises in bias voltages.
Innovation Solution
A display device with integrated sensing units that generate sense data signals based on contact, using a contact determiner to process these signals and filter out noise by calculating deviation data across multiple frames, allowing for accurate contact detection and position determination even with impulse noise present.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate touch screen panel is added to the LCD, then touch sensing functionality is provided, but cost increases, manufacturing yield decreases, and luminance deteriorates
Solution Approach 1:
The patent merges the touch sensing functionality with the LCD panel by integrating sensing units directly into the pixel structure. The sensing units utilize the existing liquid crystal layer and electrode structures to detect touch inputs, eliminating the need for a separate touch screen panel and its associated bonding processes, thereby reducing device complexity while maintaining touch sensing capability
Solution Approach 2:
The liquid crystal layer and pixel electrode structures serve dual functions: displaying images through light modulation and sensing touch inputs through capacitance or pressure changes. This multi-functionality allows the same structural elements to perform both display and touch sensing tasks, avoiding the need for additional dedicated touch sensing components
2Adaptability or versatility
If sensing units are added to detect contact, then touch detection capability is provided, but impulse noises in bias voltages cause incorrect sense data signals
Solution Approach 1:
The patent applies preliminary action by storing multiple historical sense data signals in memory before the current frame is processed. The contact determination algorithm then compares the current frame's sense data with these pre-stored historical signals to identify genuine touch contacts while filtering out impulse noises that do not conform to expected touch signal patterns
Solution Approach 2:
The system uses feedback by continuously monitoring and comparing sense data signals across multiple frames. The contact determiner analyzes the temporal characteristics of sense data changes, using feedback from previous frames to distinguish between legitimate touch inputs and transient noise, thereby improving the reliability of touch detection
Data Source
AI summary
A display device includes a display panel having a plurality of pixels, a plurality of sensing units formed in row and column directions in the display panel, each of the sensing units generating a first sense data signal based on a contact on the display panel, a sense signal processor generating second sense data signals based on the first sense data signals, and a contact determiner generating first deviation data based on the second sense data signal of a predetermined frame and the second sense data of a sample frame group, in the second sense data signals with respect to a predetermined sensing unit of the second sense data signals in a plurality of frames, generating second deviation data based on the first deviation data of a predetermined sensing unit and the first deviation data of a sample sensing unit, in the first deviation data of a predetermined frame, and determining whether a contact occurs and a contact position based on the second deviation data.